4,4{40 -Bis-{8 benzoxazolyl-(2){9 -stilbenes

ABSTRACT

The present invention provides new stilbene derivatives of the formula   WHEREIN R1 represents an alkyl group with 1 - 4 C atoms, phenyl or benzyl, and phenyl and benzyl can be substituted by chlorine or methyl. These compounds are useful optical brighteners for polyester and polyamide materials.

United States Patent 11 1 Meyer [4 1 Jan. 14, 1975 1 4,4'-BlS-[BENZOXAZOLYL-(2)]-STILBENES [75] Inventor: Hans Rudolf Meyer, Binningen,

Switzerland [73] Assignee: Ciba-Geigy AG, Basel, Switzerland [22] Filed: Oct. 16, 1972 [21] Appl. No.: 298,188

[30] Foreign Application Priority Data FOREIGN PATENTS OR APPLICATIONS 1,072,914 6/1967 Great Britain 260/240 1,072,918 6/1967 Great Britain 260/240 Primary Examiner-Henry R. Jiles Assistant ExaminerC. M. S. Jaisle Attorney, Agent, or Firm-Joseph G. Kolodny; Edward McC. Roberts; Prabodh l. Almaula [57] ABSTRACT The present invention provides new stilbene deriva tives of the formula wherein R, represents an alkyl group with 1 4 C atoms, phenyl or benzyl, and phenyl and benzyl can be substituted by chlorine or methyl.

These compounds are useful optical brighteners for polyester and polyamide materials.

4 Claims, No Drawings 4,4-BIS-[BENZOXAZOLYL-(2)1-STILBENES wheLein ll} represents an alkyl group with 1-4 C atoms,

. or p eny The invention relates to selected substitution prod- I ucts of 4,4-bis-[benzoxyzolyl-(2)]-stilbene and their Q 0 use as optical brighteners for polyester or polyamide bulk material. CH

It has already been known for a long time that 4,4'- 3 2 bis-benzoxazolyl-stilbenes can be used as optical brighteners inter alia also for the bulk brightening of on on /O polyesters and polyamides. Amongst the large number of substitution products of 4,4'-bis-benzoxazolylstilhcnc, sulphonyl derivatives have also been men- 0 0 I 2 a) Qin/ G 6112.402 N 2 2 3 tioncd as systems capable of fluorescence, without, The compounds defined above can be manufactured however, a member of these types ever having attained analogously to processes which are in themselves practical importance. In fact, it is also found that the 0 known. Appropriately, for example, stilbene-4,4- compounds hitherto mentioned if they are capable dicarboxylic acid or a derivative of this dicarboxylic of fluorescence at all give strongly greenish-tinged acid is subjected to an oxazole cyclisation reaction with effects when used in practice, that is to say their appliapproximately a two-fold molar amount of an aminocation is not of interest. phenol, in accordance with the following formulae:

o 0. no t c cn=cn c .2 x x Q a SO -R 2 (3) 4) 1 0H 0 0, no l C'CH='CH NH \p R-SO l 2 -S0 Rl O O Y /c cn=ca c\ R 0 N N 4 SO -R (1) The present invention is based on the'recognition In these formulae, X denotes a y y g p a that particularly in the case of alkylsulphonyl and lower alkOXy group of chlorine, Whilst R has the abOVephenylsulphone derivatives there exists an unexpected mentioned g.

positional dependence of the brightening effect. The 1 stage y is pp p at ly ar i d ut It has been found that selected compounds, namely at temperatures of to 200C, preferably in an those which corresp d t th f l ganic solvent which is inert towards the reactants. Ap-

whereinR denotes an alkyl group with l 4 C atoms, propriately, stilbenedicarboxylic acid chloride is used phenyl or benzyl, and phenyl and benzyl can further be and is condensed with the aminophenols in the pressubstituted y Chlorine ethyl, give extremely brilence of an organic solvent, such as dioxane, xylene,

liant brightening effects and are thus in conspicuous chlorobenzene, dichlorobenzene, trichlorobenzene or contrast to the nearest related positional isomers, the nitrobenzene, or in an inert amine such as N,N

6-alkylsulphone and 6-phenylsulphone derivatives. di th l ili idi i lin s, trierhylamine,

Within the framework of the above formula, comquinoline and the like, which bind the hydrogen halide pounds of particular practical interest are those of the liberated; the resulting yl pounds f the formula formulae (5) are then converted into the oxazole derivatives at C CH==CH C v \N temperatures of between 120 and 350C, if appropriate in the presence of a catalyst. If stilbenedicarboxylic acid chloride is used as the starting substance, it can be manufactured immediately prior to the condensation with the o-amino compound, and without isolation, from the free carboxylic acid and thionyl chloride, optionally with the addition of a catalyst (such as pyridine), in the solvent in which the condensation subsequently takes place.

The 2nd step (cyclisation reaction) then takes place at temperatures of 120 to 350C, preferably in the presence of a high-boiling inert organic solvent and optionally of a catalyst, advantageously whilst passing in a stream of an inert gas, for example'nitrogen, in order to remove the water formed in the reaction.

As organic solvents for the 2nd stage it is in part possible to use the same substances as for the 1st stage, but especially high-boiling partially polar solvents, such as dichlorobenzene, trichlorobenzene, chlorinated bipheformula (1) can in principle also be carried out in aone-step process, starting from compounds of the formula (3) and o-aminophenols of the formula (4), by

heating these components'together to elevated temperatures, appropriately between 120 and 350C, in the melt or in a solvent which at the same time acts as a condensation agent, such as polyphosphoric acid, phosphorus oxychloride or fused zinc chloride.

Amongst further possible manufacturing processes, the reaction of 4,4.-dicyanostilbene with oaminophenols of the formula (4) at elevated temperatures, preferably 160 to 260C, may be mentioned. This reaction is appropriately carried out in the presence of agents which bind ammonia such as, for example, phosphoric acid, polyphosphoric acid or phosphorus pentoxide, under an inert gas.

Another manufacturing process for compounds of the formula (1) consists of the condensation of ohalogenoanilines of the formula 'NH SO-R .Q. ca=ca are in themselves known, to give the acid amide of the formula O Hlg NH SO --R followed by cyclisation in the presence of polar solvents, such as dimethylformamide, dimethylsulphoxide, N-methylpyrrolidone or nitrobenzene, in the presence of copper catalysts such as copper-l chloride, copper-II chloride, copper oxides, elementary finely divided copper and agents which bind hydrogen halide, such as alkali acetate, magnesium oxide or organic bases such as pyridine.

The stilbenedicarboxylic acid or its derivatives, to be used as the starting material, are known.

The manufacture of 2-amino-4-methyl-sulphonylphenol and of 2-amino-4-ethyl-sulphonylphenol is described by D. Simov et al. [C.A. 66 1967) 401 m].

4-Alkylsulphonyl-Z-aminophenols or 4-benzylsulphonyl-2-aminophenols are also obtained by alkylation of l-chloro-2-nitrobenzenesulphinic acid with dialkyl sulphates such as dimethyl sulphate or diethyl sulphate, or with alkyl halides such as ethyl bromide or benzyl halides such as benzyl chloride, hydrolysis of the resulting (Ar)-alkylsulphone derivative in boiling sodium hydroxide solution to give the nitrophenols and subsequent reduction of the nitro group, for example with sodium sulphide (British Pat. No. 667.168). The higher 4-chloro-3-nitro-alkylsulphones can more readily be manufactured by nitration of the corresponding p-chloro-phenyl-alkylsulphones (U.S. Pat. No. 2,938,042).

The new compounds defined above show, in the dissolved or finely divided state, a more or less pronounced fluorescence. They can be used for the optical brightening of various synthetic organic materials, such as polyesters based on dicarboxylic acid/diol, especially saturated polyester (for example ethylene glycol terephthalic acid polyester), polyamides based on dicarboxylic acid/diamine (for example hexamethylenediamine adipate) or aminocarboxylic acids or lactams (for example polycaprolactam as well as their precondensates and co-condensates.

The organic materials to be optically brightened can be in the most diverse states of processing (raw materials, semi-finished goods or finished goods). On the other hand, they can be in the form of the most diverse shaped structures, that is to say, for example, predominantly three-dimensional articles such as slabs, profiles, injection mouldings, various machined articles, chips, granules or foams, and also as predominantly twodimensional articles such as films, sheets, lacquers, coverings, impregnations and coatings, or predominantly one-dimensional articles such as filaments, fibres, flocks and wires. The said materials can on the other hand also be present in' unshaped states, in the most diverse homogeneous or inhomogeneous forms of division, such as, for example, as powders, solutions,

condensates and prepolymers), that is to say before or LE 2 during the polymerisation polycondensafion of poly If the procedure described in Example 1 is followed addition, sprinkling Onto Polymer chips granules for but the aminophenol component used is 2-amino-4- spinning compositions, or metered addition to spinning ethylsulphonylphenol or Lamino 4 phenylsulphonyl melts or splnnlng Solutions- 5 phenol, the dibenzoxazoles of the formulae The new optical brighteners according to the present invention can also be employed as mixtures with dyestuffs (shading) or pigments (colour pigments or, in O particular, for example white pigments). CH= In certain cases the brighteners are rendered fully ef- N I fective by an after-treatment. This can consist, for ex- C H -SO, ample, of a chemical bleaching process (treatment with 5 hydrogen peroxide or chlorite).

The amount of the new optical brighteners to be used CH according to the invention, relative to the material to N be optically brightened, can vary within wide limits. A 30 C H distinct and durable effect is already achievable in cer- 2 2 5 tain cases with very small amounts, for example melting point 339 340C (after two recrystallisations amounts of 0.001 percent by weight. However, from N-methylpyrrolidone) and amounts of up to about 0.5 percent by weight can also (11) 0' be employed. For most practical requirements, I Y )QCH: amounts of between 0.005 and 0.2 percent by weight Q so N are of preferential interest.

In the examples parts, unless otherwise stated, are always parts by weight and percentages are always per- CH Q centages by weight. Unless otherwise stated, melting points and boiling points are uncorrected and are de- S0 termined in an evacuated capillary. l I o o I EXAMPLE 1 me ting point 366 368 C (after two recrystallisations from N-methylpyrrolidone) are respectively obtained. 61.0 g of stilbenedicarboxylic acid dichloride and -p y p y p is obtained. f r

7&6 g f 2- i -4 h l l h 1- h l are example, according to British Patent Specification No.

stirred into 400 ml of pyridine and the mixture is 743,907-

heated under reflux for 2 hours. It is cooled to room temperature, 400 ml of water are added and the prod- EXAMPLE 3 v uct which precipitates is filtered off and washed with If the procedure described in Example 1 is followed 100 ml of methanol and then repeatedly with water. but f: aminophenol component used is 2-amino-4- After drying, 106.0 g of the acid amide of the formula benzylsulphonylphenol, 2-amin0- -(phl p yl)- 8 l on no 1 I co cn=cn-- co 1 cn so Mi im so on 2 3 which melts, with decomposition, at about 354C are .sulphonyl-phenol or 2-amino-4-propylsulphonylb i d, phenol, the corresponding dibenzoxazoles of the forl2.l g of acid amide in 70 ml of dibut yl phthalate are mulae heated to the boil, whilst passing nitrogen over the mixture, until the amide dissolves, with cyclisation occur- I l N Q ring (approx. one-half hour) whilst at the same time the water formed, together with approx. 10 ml of solvent, Q is distilled off. After cooling to room temperature, the

precipitate is filtered off, washed twice with 10 ml of I I ethyl acetate at a time and five times with 10 ml of methanol at a time, and dried. 8.0 g of the dibenzoxazoi so lyl compound of the formula 2 2 W /0 Y O Q cn=cn N. N cn -so v so C are obtained: after 2 recrystallisations f om melting point 380C (after two recrystallisations from methylpyrrolidone with the aid of-active charcoal and N-methylpyrrolidone) and. fullers earth, the compound melts at 383 385C. melting point 400C (after two recrystallisations from at room temperature.

, n i c1-s0 SO C1 N-methylpyrrolidone) and melting point 325C (after recrystallisation from di- Y Th 2 i -4 t l l l h l) h l isomer methylformamide F dichlOfObenZene) are P mixture used as the starting product is obtained by retively obtained. 1 duction of the corresponding nitro compound, which is The 2-amin0-4-benzylsulphonyl-phen0l used as the manufactured according to J. D. Loudon [J .Chem.Soc.

starting product, of melting point 186 187C, iS Ob- 1936, 218-222], but using anhydrous iron chloride intained y reduction 0f y p y stead of aluminum chloride for the Friedel Crafts conphenol (melting point 173 174C) [Chem Abstr. 55 densatio 1961) l8647e] with Raney nickel in methylcellosolve Z-Ami o-4-( hlo ob l)- l h lh l f i melting point 217 (crystallised from n-butanol) is ob- 2-Amino-4-(p-ch ophenyl)-sulphonyl-phen0l 0f tained analogously to "2-amino-4-benzyl sulphonylmelting point 185 187C is obtained by saponifiphenol.

cation of 4,4'-dichloro-3-nitrodiphenylsulphone (J. D. 2-Amino-4-isopropyl-sulphonyl-phenol (melting Loudon and T. D. Robson, J. Chem. Soc. 1937, 242 point approx. 128 from methanol-water) and 2-amino- 246) with boiling sodium hydroxide solution to give 2- 4-n-butylsulphonyl-phenol are obtained analogously to nitro-4-(p-ch lorophenyl)-sulphony1-phenol of melting 2 -amino-4-n-propyl-sulphonyl-phenol. point 192 194C, and subsequent hydrogenation with Raney nickel in methylcellosolve. EXAMPLE 5 2-Amino-4-n-propylsulphonyl-phenol of melting 100 parts of terephthalic acid ethylene glycol polyespoint 140 141C is obtained from 4-chloro-3- ter granules are intimately mixed with 0.05 part of one nitrophenyl-n-propylsulphone (U.S. Pat.' No. 0f the comp n of the formulae 2,938,042) via 2-nitro-4-n-propylsulphonyl-phenol (13), (l4),'(15), (16), (17) or (18) and the mix- (melting point 100 101C in accordance with the ture is fused at 285C whilst stirring. After spinning the methods described above. spinning composition through customary spinning dies, 7 strongly brightened polyester fibres of good fastness-to EXAMPLE 4 I light are obtained. In a similar manner to that described 111 Example 1, EXAMPLE 6 the appropriate ammophenols yield the compounds described below: 1,000 parts of granulated polyamide-6 are mixed 3 isomer mixture (CH in the 0-position and predomi-' with 3 parts of titanium dioxide (rutile modification) nantly the p-position), melting point 323 (after recrysand 1 part of oneof the compounds of the formulae tallisation from dimethylformamide and 0- (9), (10), (1 1), (12) or (16) in a tumbler vessel for 12 dichlorobenzene). hours. The mixture is fused whilst excluding atmo- (16) '0 01G Ca -s0 I v so -cn Melting point 370 (after recrystallisation from N- pheric oxygen and the melt is spun in the usual many py and tlichlol'obenzenel ner. The filaments obtained are strongly brightened. (17) CH--SO N CH r 2 3 3 Melting point 340 (after recrystallisation from dimeth- 'ylformamide and o-dichlorobenzene). EXAMPLE 7 A150 An intimate mixture of parts of polyvinyl chlo- 9 10 ride, 3 parts, of stabiliser (Advasta t ED 100; Ba/Cd erein R represents an alkyl group with 1 4 C atoms, complex), 2 parts of titanium dioxide, 59 parts of diocor phenyl.

tyl phthalate and 0.01 to 0.2 part of one of the compounds of the form f 3. The compound according to claim 1, co'rrespond-' is milled on a calender at 150-155 to give an opaque i t0 h f l film. This has a significantly higher degree of whiteness than a film which does not contain the optical brightener. C -CH= I claim: 2 N

CH -S-O N 4. The compound according to claim 1, correspo d. ZT l ing to the formula 1. A stilbene derivative of the formula wherein R represents an alkyl group with l 4 C 20 atoms, phenyl or benzyl, and phenyl and benzyl can be substituted by chlorine or methyl. N/ Q 2. A stilbene derivative according to claim I, come CH 2 spending to the formula N I 7* o n cn-Gcf 0 -R V i 2 r.

IQ so -cn 

2. A stilbene derivative according to claim 1, corresponding to the formula
 3. The compound according to claim 1, corresponding to the formula
 4. The compound according to claim 1, corresponding to the formula 